The present invention relates to a method of fabricating a clean room filter bank, of the type adapted to supply highly filtered air to a work area under substantially laminer flow conditions, and wherein the components of the filter bank are maintained in a contaminant free condition during their manufacture, storage, shipment, and final assembly at the clean room site.
The need for a controlled, contaminate free work area is well recognized in industry wherever precision manufacturing and assembly operations are conducted, and several clean room designs have been developed for this purpose. In one such prior design, the clean room comprises a room-like enclosure having a horizontal filter bank suspended from and overlying the entire ceiling. The filter bank includes a number of individual high efficiency filters supported on a rectangular latticework, and a blower introduces air under pressure into the open plenum chamber formed between the filter bank and ceiling. The air then passes downwardly through the filters and vertically through the clean room. Appropriate ducts are provided in or adjacent the floor for conveying the air back to the blower for recirculation.
Copending and commonly owned U.S. patent applications 733,971 and 733,972, now Pat. Nos. 4,671,811 and 4,678,487 respectively each disclose a clean room of the above design. In addition, these copending applications disclose a supporting horizontal latticework composed of a plurality of interconnected channel members arranged in a rectangular pattern so as to define rectangular open areas. The channel members have the configuration of an inverted A in cross section, and so that the channel members define an upwardly open receptacle. A gum-like sealant is disposed in the receptacles after the complete assembly of the latticework, so that a continuous uninterrupted strip of sealant extends about the periphery of each open area. As a final step in the fabrication of the filter bank, the filters are positioned to overlie the open areas, and the filters include peripheral skirts which are embedded in the sealant to seal the filters to the latticework.
While the above disclosed clean room design has achieved widespread acceptance in the industry, the installation procedure remains time consuming and tedious, particularly with respect to the installation of the sealant into the receptacles of the channel members since the sealant installation takes place after assembly of the latticework and adjacent the ceiling of the clean room. In addition, the fabrication of the latticework can result in dust and debris being caught in the receptacles and the sealant, and this foreign matter can interfere with the seal of the filters, and it can also become dislodged during subsequent use of the clean room so as to cause contamination of the sensitive products in the room.
It is accordingly an object of the present invention to provide a method of fabricating a clean room filter bank which effectively alleviates the above problems and limitations in the prior art.
It is a more particular object of the present invention to provide a method of fabricating a clean room filter bank which protects the components of the supporting latticework from contamination by foreign materials, throughout the manufacturing process of the components, shipment and storage of the components, and also during the assembly of the components into a filter bank.
It is a further object of the present invention to provide a method of fabricating a clean room filter bank which significantly reduces the amount of the sealant which is deposited into the receptacles after the fabrication of the latticework, and so as to simplify the installation process.
It is still another object of the present invention to provide a channel member which is adapted to be fabricated into a supporting latticework for a clean room filter bank, and wherein the sealant can be assembled with the channel member under clean room conditions at the factory, with the clean conditions being preserved during shipment, storage, and final assembly of the channel member into the latticework of the filter bank.